Material storage structures and bins have been provided with visual indicators to provide a person with information concerning the level and amount of material located in the structures and bins. Examples of visual indicators attached to bins to provide visual information regarding the level of material stored in the bins are shown and described in the following U.S. patents.
P. Swanson in U.S. Pat. No. 910,606 discloses a coal bin having vertically spaced visual indicators along an upright wall of the bin. Each indicator has a plate pivotally supported on the inside of the upright wall and a pair of plates hinged to the outside of the upright wall. A rod extended through a hole in the upright wall is pivotally connected to the plates. Coal in the bin forces the inside plate against the upright wall and moves the outside plate to an upright position. A person standing adjacent the bin can look at the upright plate to ascertain whether it is loaded, empty or partially filled up with coal.
A. Enderud in U.S. Pat. No. 2,260,661 discloses a gauge for indicating the level of seed grain in a seed box. A shaft rotatably mounted on the seed box is connected to a scale located adjacent the outside of the seed box. An arm is joined to the inside end of the shaft. The lower end of the arm supports a rider or float. The rider moves up and down with the level of seed grain in the seed box causing the indicator of the gauge to move thereby providing a visual indication of the level of seed grain in the seed box.
J. R. Ray in U.S. Pat. No. 2,718,867 discloses a material level indicator for a bin. A bin wall has an opening covered with a mounting plate. Brackets secured to the mounting plate pivotally support a visual flag for movement between vertical and horizontal positions. An inverted V-shaped member secured to the plate extends horizontally into the chamber of the bin. An arm pivotally mounted on the member extended downwardly is attached to a paddle adapted to contact the material in the bin. A linkage connected to the arm and flag transmits pivotal movement of the arm to pivot the flag between the vertical and horizontal positions that provide visual information regarding the level of the material in the bin.
F. M. Lau in U.S. Pat. No. 3,210,493 discloses a bin level sensing device having a sensing arm pivotally mounted with a spherical bearing on a housing. A ball is attached to the outer end of the arm. A motor operates to move the arm and ball in a circular path. When ball engages material in the bin, the motor stalls and closes a microswitch thereby providing information relative to the level of material in the bin.
L. W. Watkins in U.S. Pat. No. 3,290,462 discloses a bin level switch operable to control an alarm signal or relays to shut off the feed of coal to a bin. A rigid rod connected to a coupling having a spherical head extended down into the bin engages the coal in the bin. A shield attached to the rod protects the rod from the impact of lumps of coal rolling down in the bin. An arm connected to the coupling has an upper end engageable with an actuator of an electric switch. When the level of the coal in the bin moves the rod laterally, the arm swings away from the switch actuator whereby the switch is turned on activating the alarm.
R. V. Zimmerman in U.S. Pat. No. 3,685,356 discloses a level indicator for granular material being discharged in a bin. The indicator has a feeler arm arranged to sit on the side of a conical pile of granular material in the bin. A mechanical linkage including a shaft and arms transmit motion to a useable mechanical or electrical signal used for the detection, indication and/or control of the level of the pile of granular material in the bin.
T. C. Johnson and L. W. Johnson in U.S. Pat. No. 4,799,383 disclose a visual indicator for providing a positive visual indication of the level of grain in a bin. The indicator has a sealed chamber filled with an opaque liquid. A contrasting plug secured to a diaphragm is movable in response to an actuator located in the bin between an OFF position obscured by the liquid and an ON position wherein the plug is visible upon displacement of the liquid. The actuator includes a resilient dome that collapses in response to pressure of the grain in the bin.
L. W. Johnson and T. C. Johnson in U.S. Pat. No. 4,829,820 disclose a visual indicator operable to provide positive ON and OFF visual information to a person of the level of grain in a bin. This indicator has the opaque liquid and plug disclosed in U.S. Pat. No. 4,799,383. The actuator has an arm pivoted to a housing. A pressure plate secured to the bottom of the arm is moved by the pressure of grain in the bin whereby the arm applies a force to a stem operatively connected to the plug to move the plug between an OFF position obscured by the liquid and an ON position wherein the plug is visible upon displacement of the liquid. A spring biases the plug and arm to the OFF position.
L. W. Johnson and T. C. Johnson in U.S. Pat. No. 5,088,323 disclose a visual indicator having an actuator connected to a mounting bracket. The bracket and actuator extends through a hole in the side wall of a bin. Part of the bracket and actuator is moved from the outside of the bin wall through the hole to the inside of the bin. The actuator has a lever pivotally mounted on the bracket and pressure plates connected to the lever. A bag attached to the bracket surrounds the pressure plates. The presence of grain in the bin causes the bag to collapse whereby the entire force acting on the bag is transmitted to the pressure plates to activate the visual indicator. An alternative actuator has a triangle-shaped collapsible plate connected to a force transmitting cup and a motion restriction washer. A bolt and threaded insert connects the pressure plate 290 to the washer and cup.
L. W. Johnson and T. C. Johnson in U.S. Pat. No. 6,067,927 disclose a visual indicator secured to the side wall of a material storage bin that operates to provide a person with visual information concerning the level of materials in the bin. The indicator has a body supporting rotatable visual members having contrasting colored portions covered with a transparent lens. An arm pivotally mounted on the body operates a motion transmission gear assembly that selectively rotates the visual members between ON and OFF positions. An actuator responsive to the material in the bin is operatively connected to the arm to pivot the arm to cause the motion transmission gear assembly to rotate the visual members between ON and OFF positions thereby providing visual information of the level of material in the bin.